There are no metal parts within this tape measure, as it is not insulated but non-conductive, this is a huge technical difference, the tape will not hold a current, therefore can be used in all sorts of circumstances. The tape itself is made from the highest quality FRP material, that will not stretch, enabling the tape to last for several years of steady use. Proof tested to 20kV this tape is proving to be an invaluable aid in the utilities industry the world over.